Figure 4

Role of p53 in NO-induced death in SH-SY5Y cells overexpressing parkin. A, Validation of p53-shRNA as a gene-silencing tool. SH-SY5Y cells were transfected with control (ctrl)- or p53 shRNA encoding plasmids, and the cell lysates subjected to western blotting using anti-p53 or actin antibodies. The optical density of the p53 bands was quantified and normalized to actin, n = 3; * p < 0.01. B, Histological images of SH-SY5Y cells transiently transfected with pcDNA or parkin plasmid. Cells were co-transfected with ctrl- or p53-shRNA plasmids that also encoded GFP (green). Cells were exposed to 600 μM old or fresh SNOC 24 h prior to TUNEL (red) staining. Scale bar: 20 μm. C, Percentage of TUNEL-positive cells among GFP-positive cells under the designated conditions. Values are mean + SEM of 41–83 cells per condition performed in triplicate experiments; * p < 0.05. D, Schematic representation of the pathway linking NO to apoptosis in this system.